RU2763644C1 - Transosseous automated distraction apparatus and an automatic displacement unit - Google Patents

Abstract

FIELD: medicine.

SUBSTANCE: inventions group relates to medicine, namely to a transosseous automated distraction apparatus and an automatic displacement unit. The transosseous automated distraction apparatus contains supports interconnected by automatic displacement units, each of which includes a housing, a gear motor, electrically connected to the controller, and a lead screw with a nut. The automatic displacement unit is made with a gear transmission located in it, which connects the lead screw and the gear motor, the lead screw nut is made of a cold-flowing antifriction fluorine-containing polymer and is installed with the possibility of end compression, a sector disk is mounted in the housing, fixed on one of the gears of the gear drive, and its rotation sensor, electrically coupled to the controller. The controller is located inside the body of the automatic displacement unit; at the point of attachment of the lead screw, there is a sensor of the longitudinal force of the lead screw, which is electrically connected to the controller.

EFFECT: invention provides dosed movement of the supports of the external fixation device while reducing the mass and dimensions of the device with the provision of feedback in the form of control of the emerging forces at the point of attachment of the lead screw.

5 cl, 3 dwg

Description

The field of technology.

The invention relates to the field of medical technology, in particular to devices for external skeletal fixation ( hereinafter also "apparatus") with electromechanical drives, to devices used in traumatology and orthopedics for automatic dosed movement of bone fragments.

The level of technology.

The problems of rehabilitation of patients with congenital pathology of the musculoskeletal system, disabled people with consequences of injuries of the upper and lower extremities continue to excite orthopedists in all countries of the world. Among patients applying to orthopedic centers, in 80% of cases it is required to resolve issues of limb lengthening or correction of deformities with simultaneous distraction of bone fragments.

Among the numerous methods of limb lengthening, transosseous distraction osteosynthesis according to the Ilizarov method remains the method of choice today. The main principles on which the Ilizarov method is based include stable fixation of bone fragments, a saving attitude to osteogenic tissues, their good blood supply, the optimal pace and rhythm of distraction, the possibility of functional load on the limb during lengthening [Shevtsov V.I., Popkov A.V. ., 1998].

Improving the process of limb lengthening, orthopedists in different countries came to the need to automate this process [Ilizarov G.A., 1981; Popkov A.V., 2008; G.A. Uriev, O.A. Sokolovsky, I.A. Ilyasevich, A.V. Zarovskaya, 2008].

To date, devices are known that provide limb lengthening in automatic mode (see patents: US 4615338; US 4973331; RU 1122308; RU 423114; RU 30073). In which various designs of automatic displacement units (automatic distraction units) are used, providing a dosed mutual movement of the apparatus supports together with bone fragments fixed in them. However, all of them have disadvantages, such as relatively high weight and dimensions associated with the execution of the control unit, as well as the lack of feedback. Since the apparatus is part of the biotechnical system apparatus-organism. Between the impact of the device on the body and the result of this impact, a feedback should be established, which performs a controlling function to ensure the quality of control over the processes of movement and regeneration. The control subsystem (organism) must correct the modes of the controlled subsystem (apparatus) through efferent connections. Therefore, devices in the future will have a third subsystem - effector. The biotechnical system apparatus-organism will become more self-regulating, i.e. it will acquire adaptability.

As feedback elements, first of all, force-measuring sensors that control the force of distraction and compression can be used [Popkov A.V., 1977; Meyrueis J.P. et al., 1980; Domres B, Neugebauer W., 1980; patent RU 3085; patent RU 4675]. However, the use of mechanical force-measuring sensors significantly increases the dimensions of the external fixation device, and the measurement accuracy leaves much to be desired. Strain gauge sensors used in external fixation devices, being highly sensitive, give a huge measurement error at the slightest asymmetry in the installation of the measuring element (patent RU No. 227739 - A group of inventions provides for the organization of digital visualization of compression and distraction processes in transosseous devices, increasing the accuracy of repositioning bone fragments, the accuracy of setting compression load and gap between fragments).

In the Ilizarov Center, the experimental substantiation of the use and introduction of an automatic variant of limb bone lengthening began in 1981. Despite the fact that the clinical effectiveness of the used automatic drives has been proven, some inconveniences of their use have been identified. Products differed in large dimensions and considerable weight. The number of connected gearmotors was no more than four, which limited the use of an autodistractor for some types of external fixing structures (Taylor, ORTO-SUV). There was no feedback function depending on the dynamics of the distraction efforts of the external fixation device. All this led to the need to develop a new generation of automatic distractors.

From the existing prior art known compression-distraction device Platov (Patent RU 2061421, publ.: 10.06.96., bull. 161), which contains rings with specially made mounting holes, and spokes. The rings are interconnected by automatic distraction nodes (displacement nodes), each of which includes a gear motor electrically connected to the control unit, roller screw pairs with intermediate rolling elements. When this lead screw is connected coaxially with the output shaft of the motor-reducer.

However, this device does not provide equality of displacements in screw pairs in each cycle of operation due to the dependence of the number of engine revolutions on the load and the degree of discharge of the batteries, which leads to a curvature of the formed bone regenerate. In addition, the location of the distraction nodes (displacement nodes) in the apparatus is determined by the design of the support rings, which limits the possible directions of the wires and the places of their fixation. At the same time, the complexity of the design of roller screw pairs increases the cost of the product, and the location of the motor-reducers outside the gap between the support rings increases the dimensions of the apparatus. The device does not have a feedback system based on the measurement of distraction or compression forces.

A compression-distraction apparatus is known (A.S. SU 1423114 USSR MKI5 A61V 17/58 Publ. 15.09.88; Bull. No. 34.), containing supports with a threaded rod connected to a drive device (automatic displacement unit), including a housing with branch pipe, a ratchet wheel mounted on a threaded rod, a power element made of a material with a memory effect, connected to a spring, a ratchet and having a heater electrically connected to the control unit and power source.

However, this device does not develop the necessary forces of distraction to lengthen limb segments in adult patients, has a low efficiency, and the heat loss of the heater requires operation at a sufficiently high ambient temperature and causes frequent replacement of the power source. The device does not have the ability to measure distraction forces.

A device for osteosynthesis with an automatic control system is known (patent RU 143975). It contains supports connected by electric drives with spokes fixed on them, a control unit with a power source and a programmable controller, electrically connected with electric drives, position sensors, a programming unit with a liquid crystal display. Moreover, the programming unit is connected to the control unit only for the time of entering programs. The programming unit is equipped with an interface for connecting to a personal computer in the form of a USB connector, a touch panel, a programmable microcontroller, a touch panel driver, and a voltage stabilizer. The control unit is fixed on the support of the device and contains a real-time clock, a clock power supply, non-volatile memory, drivers of electric drives, equipped with an emergency shutdown system for electric drives, in the form of a button, light and sound indication of the operating mode, using a speaker and LED, as well as a connector for connecting programming block. The use of the device allows for automatic dosed movement of bone fragments, with a given rate of distraction and control of parameters.

The control unit is fixed on the support of the device and the control and feedback components are located outside the body of the electric drives, which increases the dimensions and weight of the control unit and the device.

Known transosseous apparatus (patent RU 30073), containing supports with spokes, interconnected by automatic distraction nodes (automatic movement nodes), each of which includes a gear motor electrically connected to the control unit. The automatic distraction unit is made in the form of a platform with a gear pair placed on it, connecting the lead screw and the gear motor located on the side of the gear pair, and the lead screw nut is made of a cold-flowing antifriction fluorine-containing polymer, while an optocoupler is mounted on the platform, electrically connected with a control unit, equipped with a perforated disk mounted on one of the gears of the gear pair.

The disadvantage of this model is the need for a separately placed control unit of large weight and dimensions, the distraction rate is limited to 2 mm / day, the insignificant thickness of the gear pair leads to frequent gaps in the screw pairs and disturbances in the transmission of motor-reducer forces. This device does not have a force-measuring sensor, which excludes the creation of a feedback system in the process of distraction osteosynthesis. The control unit placed outside the body of the automatic distraction assembly significantly increases the dimensions and weight of the apparatus.

The essence of the technical solution.

The objective of the invention is to provide the possibility of round-the-clock dosed controlled movement of bone fragments for limb lengthening with apparatus-organism feedback.

EFFECT: technical result consists in ensuring controlled movement of supports of the external fixation device, while reducing the weight and dimensions of the device, providing feedback in the form of control of the forces occurring at the point of attachment of the lead screw. EFFECT: invention provides the possibility of highly fractional round-the-clock spatial displacement of bone fragments in automatic control mode with a given rhythm and distraction speed. Improved design reliability.

Moreover, the control and monitoring components are integrated into the automatic movement unit.

The invention in one aspect relates to the actual design of the automatic movement unit.

The technical result is achieved by the fact that the automatic displacement unit for the transosseous automated distraction apparatus includes a housing, a gear motor and a lead screw with a nut, a gear transmission is placed in the housing, connecting the lead screw and the gear motor, the lead screw nut is made of cold-flowing antifriction fluorine-containing polymer and installed with the possibility of end preload, a sector disk mounted on one of the gears of the gear drive and a sector disk rotation sensor are mounted in the housing. Inside the housing with the motor-reducer, there is a controller electrically connected to the sector disk rotation sensor, and in the place where the lead screw is attached, a longitudinal force sensor of the lead screw is installed, which is electrically connected to the controller.

The invention in another aspect relates to the actual design of the transosseous automated distraction apparatus.

The technical result is achieved by the fact that the transosseous automated distraction apparatus contains supports interconnected by automatic movement units, each of which includes a gear motor electrically connected to the controller, and a lead screw with a nut, moreover, the automatic movement unit is made in the form of a housing with a gear transmission placed in it, connecting the lead screw and the motor-reducer, the lead screw nut is made of cold-flowing antifriction fluorine-containing polymer and installed with the possibility of end preload, a sector disk is mounted in the housing, fixed on one of the gears of the gear and a sector rotation sensor disk electrically connected to the controller. The sector controller is located inside the housing of the automatic displacement unit, at the point of attachment of the lead screw, a longitudinal force sensor of the lead screw is installed, electrically connected to the controller.

Moreover, the power source is located in the base unit, to which from 1 to 6 automatic movement units are connected.

The invention is illustrated by images:

fig. 1 - scheme, transosseous automated distraction apparatus;

Fig. 2 - image of the 3d model, automatic movement unit, the body is shown as transparent;

Fig. 3 - image of the base unit.

Specification:

1 - base block;

2, 7 - supports;

3 - nut;

4 - lead screw;

5 - controller;

6- motor-reducer;

8- sensor of the longitudinal force of the lead screw;

9 - sector disk rotation sensor;

10 - body;

11 - driven gear;

12- intermediate gear;

13 - sector disk;

14 - drive gear;

15- thrust bearing.

Implementation of the invention.

Transosseous automated distraction apparatus (figure 1) contains a base unit 1 (figure 3) designed to accommodate a power source and communication elements with external data processing devices (personal computer, smartphone, etc.), supports 2 and 7 with spokes and /or bone screws, for fastening to bone fragments. Supports 2 and 7 are interconnected by automatic displacement units (figure 2), each of which includes a gear motor 6 electrically connected to the controller 10, and a lead screw 4 with a nut 3. Moreover, the automatic displacement unit is made in the form of a housing 10 with a gear placed in it, connecting the lead screw 4 and the gear motor 6. The lead screw nut 3 is made of a cold-flowing antifriction fluorine-containing polymer and is installed with the possibility of end preload. Nut 3 is installed in a tube (not indicated) with the possibility of end compression by means of a hollow pusher screwed into the tube. In the housing 10, a sector disk 13 is mounted, fixed on one of the gears (14) of the gear train and a sector disk rotation sensor 9 electrically connected to the controller 5. The controller 5 is located inside the housing 10 of the automatic displacement unit. At the point of attachment of the lead screw 4, a sensor 8 of the longitudinal force of the lead screw is installed, which is electrically connected to the controller 5.

The automatic displacement unit for the transosseous automated distraction apparatus includes a housing 10, a gear motor 6, and a lead screw 4 with a nut 3. The housing 10 contains a gear train, including a driven gear wheel 11, an intermediate gear wheel 12, a drive gear wheel 14, connecting the lead screw 4 and the motor-reducer 6. The nut 3 of the lead screw 4 is made of a cold-flowing antifriction fluorine-containing polymer and is installed with the possibility of end preload, using a pusher (not indicated). In the housing 10, a sector disk 13 is mounted, fixed on one of the gears (14) of the gear train and a rotation sensor 9 of the sector disk 13. Inside the housing 10, next to the motor-reducer 6, there is a controller 5 electrically connected to the rotation sensor 9 of the sector disk 13. at the place of fastening of the lead screw 4, a thrust bearing 15 and a sensor 8 of the longitudinal force of the lead screw 4 are installed, electrically connected to the controller 5.

The transosseous automated distraction apparatus contains supports with pins or bone screws (screw rods). The base unit 1 is connected to automatic transfer units from 1 to 6 pieces, depending on the set medical tasks and the selected design of the external fixation device.

The motor-reducer 6 is electrically connected to the controller 5 and the base unit 1 to ensure work at a given pace of distraction, control-displacement control. The base unit contains electronic components with a computer program in which the parameters of limb elongation are laid down on the principles of feedback with the dynamics of distraction forces, for which the lead screw 4 rests in the housing through the support bearing 15 on the strain gauge sensor 8 of the longitudinal force of the lead screw 4, and the controller 5 of the components (sensor longitudinal forces, sector disk rotation sensor, gear motor) is located inside the housing. The power supply of the movement node is carried out from AA batteries placed in the base unit 1. The base unit 1 also provides a reflection of the amount of movement of the bone fragments of the limb and changes in the limb lengthening program through feedback with the dynamics of distraction forces displayed on a smartphone, tablet or PC.

The body 10 of the automatic displacement unit at the base contains a platform (not indicated) on which the elements of the gear train are placed and on which the casing of the gear motor 6 is attached.

The transosseous automated distraction apparatus thus has intelligent feedback to the distraction force control system during automated limb lengthening.

The placement of the processor control board with the controller 5 in the housing 10 of the automatic movement unit makes it possible to make the design compact and more reliable in operation.

The system of control and movement is formed on the principle of feedback in the control of distraction forces arising in the apparatus (in total from all movement nodes):

- the normal process of elongation is accompanied by a gradual increase in distraction forces from 0 to 600N and under these conditions the control program does not change the rate and rhythm of distraction;

- with a reduced process of reparative regeneration of bone tissue, when the level of distraction forces reaches a plateau of 200-250N, the control program reduces the rate of distraction to 0.5 mm/day without changing it until the end of the lengthening process;

- in the event of a sudden discontinuity of the distraction regenerate (increased rate of distraction), there is a sharp decrease in the level of distraction efforts, and under these conditions, the control program first reduces the rate of distraction by half and, with a further decrease in the level of distraction forces, stops the lengthening for 7 days after another day, reporting the problem to the attending physician through light signaling and on electronic media. In the absence of instructions from the attending physician, after 7 days, distraction will automatically continue at a rate of 0.5 mm per day with control over the dynamics of distraction efforts;

- with an increased process of reparative regeneration of bone tissue (danger of premature consolidation of bone fragments), there is a sharp increase in the level of distraction forces by 100-150N in 1-2 days, and under these conditions, the control unit increases the rate of distraction to 2, and in a day to 3 mm / day , turns on the light notification of the attending physician and continues the distraction at an increased pace. After reaching the level of distraction forces of 600-700N, the elongation stops.

Transosseous automated distraction apparatus of the Ilizarov type (TM).

The Ilizarov robotic apparatus has supports 2 and 7 interconnected by automatic movement units (from 1 to 6 units, depending on the assigned medical task), each of which contains a body 10 fixed on one support, in which a gear motor 6 is installed, a gear transmission transmitting the rotational force of the gearbox to the lead screw 4 passing through the nut 3 made of antifriction material installed in the tube and pressed along the end by a hollow pusher that transmits the tensile force to another support, an optocoupler equipped with a sectoral disk, and a remote base unit 1 for controlling the motor -reducer 6, electrically connected to the movement nodes by means of a cable. To measure the tensile force between supports 2 and 7 and automatically correct the distraction force, the lead screw 4 relies on a strain gauge force sensor 8 installed in the housing 10 and electrically connected to the processor control board with the controller 5 to control the motor-reducer 6, also located in the housing 10 and connected by wires to the output of the optocoupler of the sensor 8 of the position of the shaft of the motor-reducer 6, containing a perforated sector disk 13 planted on the shaft and a reflector (not indicated) installed in the housing 10.

At the same time, to reduce the dimensions of the housing 10, the gear train has an intermediate gear 14, and the control board with the controller 5 is electrically connected via a connecting cable of three wires to the base control unit 1, into which the treatment program is entered, expressed through the dynamics of distraction forces and displayed on a smartphone, tablet or PC, as well as the recorded current results of treatment, and the exchange of information between the base control unit 1 and the board with the controller 5 for controlling the motor-reducer 6 is carried out over one wire of the connecting cable, while two wires of the cable are powered from placed in control unit of chemical batteries, which reduces the number of wires to three for each automatic movement unit.

use of the invention.

The automatic movement unit is installed between supports 2 and 7 of the external fixation device in the amount from one to six, depending on the set medical task and the selected model of the external fixation device. Thus, a transosseous automated distraction apparatus is formed, which is mounted on the limb. The body 10 and nut 3 are fastened with elements of the apparatus kits (nuts and bolts), while maintaining the general longitudinal direction of the load on the lead screw 4. After connecting the automatic displacement unit to the base unit 1 and selecting the limb lengthening program, the distraction process is started. The incoming electrical signal from the control unit 1 turns on the motor-reducer 6, which transmits rotation through the drive gear 14 and the intermediate gear 12 to the driven gear 11, mounted on the lead screw 4. The rotation of the lead screw in the hollow nut 3 leads to an increase in the distance between the supports 2 and 7 of the apparatus, therefore, to the movement of bone fragments associated with them with wires and/or bone screws. At the moment of passage of the light beam of the optocoupler including the sector disk 13 and the sensor 9 through the hole of the sector disk 13, an electrical signal is sent to the controller 5 to turn off the motor-reducer 6.

The subsequent activation of the motor-reducer 6 is carried out after a predetermined period of time, depending on the selected tempo and rhythm of distraction.

In the proposed apparatus, control over the value of the angle of rotation of the lead screw 4 by means of an optocoupler with a rotation sensor 9 of the sector disk 13 ensures the equality of micro-movements in each cycle of operation.

The presence of an intermediate gear wheel 12 eliminates possible gaps and jamming during rotation.

The controller 10 of the components of the automatic displacement unit, located inside the housing 10, serves the operation of the motor-reducer 6, the rotation sensor of the sector disk 9 and the sensor 8 of the longitudinal force of the lead screw 4.

Support bearing 15 ensures the transmission of the longitudinal load of the lead screw 4 to the sensor 8 of the longitudinal force of the lead screw 4.

Making nut 3 from PTFE simplifies and reduces the cost of the transosseous apparatus design, and the physical and mechanical properties of its material and the possibility of preloading eliminate the risk of thread jamming, provide a low coefficient of friction and the ability to eliminate gaps in the screw pair.

The use of the space occupied by the motor-reducer 6 between the supports 2 and 7 to accommodate the screw pair reduces the dimensions of the apparatus, the use of the space inside the housing 10 to accommodate the electronic components of the controller 5 makes it possible to reduce the number, size and weight of structural elements of the apparatus placed outside it, allows to reduce the overall dimensions and the mass of the device and increase its reliability, security of parts vulnerable to damage.

Base unit 1 and controller 5 are designed for automatic control of mechanisms according to a pre-compiled program.

Depending on the selected distraction/compression rate, for each automatic displacement node (hereinafter also referred to as the “auto-distractor”), the period of time is calculated after which it must be turned on. The calculated value of the period with additional information (mode: distraction / compression, hours of operation during the day) is stored in the memory of the base unit as a control program. The size of the control program is 60 days. The rate of distraction/compression (on period) is set for each day and for each auto-distractor separately.

The program performs periodic inclusion of autodistractors with a given period. For the convenience of the patient, the program includes working hours during the day. If necessary, you can set the time when the auto-distractors will not turn on. The turn-on period of the auto-distractors is then adjusted to maintain the given distraction/compression rate.

To indicate the status, the base unit 1 includes: an indicator of the operating mode (yellow - “STOP”, green - “OPERATION”, red flashing - “FAIL”), a low battery indicator and an audible alarm duplicating the light indication “FAIL”.

The controls are the STOP/RUN button and the power switch.

The task of the autodistractor control program is carried out through the programming connector located in the battery compartment.

During the operation of the autodistractor, power is supplied to the feedback sensor, which controls the movement of the autodistractor rod. If within 8s (maximum engine rotation time) no voltage level drops are detected at the output of the feedback sensor, the electronic control unit will issue an audible and light error signal.

If the operating time of several autodistractors coincided, then one of them is turned on first, and only after the first autodistractor has completely stopped, the next one is turned on.

Claims (5)

1. A transosseous automated distraction apparatus containing supports interconnected by automatic displacement units, each of which includes a gear motor electrically connected to the controller, and a lead screw with a nut, moreover, the automatic displacement unit is made in the form of a housing with a gear connecting the lead screw and the gear motor, the lead screw nut is made of cold-flowing antifriction fluorine-containing polymer and installed with the possibility of end preload, a sector disk is mounted in the housing, fixed on one of the gears of the gear, and a sector disk rotation sensor, electrically associated with the controller, characterized in that the controller is located inside the housing of the automatic movement unit, in the place where the lead screw is attached, a longitudinal force sensor of the lead screw is installed, electrically connected to the controller. 2. Transosseous automated distraction apparatus according to claim 1, characterized in that the power supply of the automatic movement unit is carried out from AA batteries placed in the base unit. 3. The transosseous automated distraction apparatus according to claim 1, characterized in that the body of the automatic displacement unit at the base contains a platform on which elements of the gear train are placed, with the possibility of attaching the casing of the motor-reducer to it. 4. Transosseous automated distraction apparatus according to claim 1, characterized in that it has supports 2 and 7 interconnected by automatic movement units, each of which contains a body fixed on one support, in which a gear motor is installed, a gear transmission that transmits force reducer rotation to the lead screw passing through a nut made of antifriction material installed in a tube and pressed along the end by a hollow pusher that transmits the tension force to another support, an optocoupler equipped with a sector disk, and a remote base unit for controlling the gearmotor, electrically connected to the nodes movement by means of a cable, a lead screw configured to rely on a strain gauge force sensor installed in the housing and electrically connected to the processor control board with a controller for controlling the gearmotor, also located in the housing and connected by wires to the output of the optocoupler of the motor-reducer shaft position sensor , sod holding a perforated sector disk planted on the shaft and a reflector installed in the housing, a control board with a controller, electrically connected via a connecting cable of three wires to the main control unit, configured to enter a treatment program expressed through the dynamics of distraction forces and displayed on a smartphone, tablet or a personal computer, one wire of the connecting cable is configured to exchange information between the main control unit and the board with the controller for controlling the motor-reducer, while two wires of the cable are configured to supply power from the chemical batteries located in the control unit. 5. Automatic displacement unit for a transosseous automated distraction apparatus, including a housing, a gear motor and a lead screw with a nut, a gear transmission is placed in the housing, connecting the lead screw and the gear motor, the lead screw nut is made of cold-flowing anti-friction fluorine-containing polymer and mounted with the possibility of end preload, a sector disk is mounted in the housing, fixed on one of the gears of the gear train, and a sector disk rotation sensor, characterized in that a controller is located inside the housing with a motor-reducer, electrically connected to the sector disk rotation sensor, and in the lead screw attachment point is equipped with a lead screw longitudinal force sensor electrically connected to the controller.

Images